A spokesman for the governor of Helmand Province, Omar Zwak, told RFE/RL's Radio Free Afghanistan on January 10 that U.S. Marines mistakenly shot the boy in an incident two days previously because visibility was poor.

Reuters quotes a spokesman for the NATO-led force in Afghanistan as saying the matter would be investigated and that all possible measures are taken to avoid civilian casualties.

A spokesman for Afghan President Hamid Karzai, Aimal Faizi, said Kabul has called for an end to military operations on homes and villages to avoid such killings.

Afghan-U.S. relations have recently been damaged by Karzai's refusal to sign what Washington considers to be a key bilateral security deal.

Three NATO Personnel Killed In 'Aircraft Mishap'

Elsewhere in Afghanistan, three NATO personnel have died after an "aircraft mishap" in eastern Afghanistan.

The NATO-led International Security Assistance Force (ISAF) did not say exactly where the incident took place or the nationalities of those killed -- two of whom were service members and the other a civilian employee.

However, U.S. media said all three were Americans.

The crash comes shortly after an ISAF spokesman confirmed that a Blackhawk helicopter crash in mid-December that killed six U.S. soldiers was the result of "enemy action."

At the time of the crash, on December 17, U.S. defense officials said there had been no indications that enemy fire had brought down the helicopter